General Technologies FF300 Fault Finder for Electrical Wiring Open / Short Circuit - Manual (Page 5)

Fig.2 - Set up for tracing short or
open circuits, or location
of wiring
Fig.3 - Set up for tracing short
and open circuits, or
tracing wiring
Fig.4 - Set up for tracing open
circuits or identification
of wires
Fig.5 - Set up for upstream
tracing of open circuits
or location of wires
11- Hook up reference chart
Page 7 Page 6
• For identifying wires without load connected: Connect transmitter as described in
section ‘9- Locating Open Circuits’,to the circuit to be identified. Then proceed to
scan all suspected wiring with the FF300R’s probe until the flashing and beeping is
at its maximum. In the case of tightly packed wires( bundles, conduits, etc.), it may
be necessary to spread these apart to facilitate the identification process of a particu-
lar wire.
12 - General Procedures
Short and Open Circuit operation – Differences:
The FF300 FaultFinder uses two different types of signals to trace either short or open
circuits. Understanding its differences, as explained in the following paragraphs will allow
you to make the most effective use of this versatile tool.
12.1 Working with open circuits
On detection of an open circuit, the FF300T injects a special radio signal into the
circuit, which can be picked up by the FF300R (tracer) probe.
When tracing an open circuit, keep in mind that RF (radio frequency) signals injected
in the faulty wire being traced; will be easily absorbed by any other conductor nearby.
(ie: other wires, metal frames, etc.).
Fig. 6 - Detection field when tracing open circuit with the FF300
The effect of this absorption may vary from a reduction in the tracer’s range, to a total
shielding of the signal with no detection being possible at all (See Fig. 6).
In order to avoid confusing a shielded portion of the faulty wire with the actual fault
on it, the circuit should be checked on all possible sections to confirm that no signal
is picked up on one side of the suspected faulty section.
Hint: In some cases when tracing open circuits, connecting the FF300
transmitter’s clip with the slotted wire to the faulty wire, and the clip with the
flat wire to ground or positive supply will improve the tracer’s range.
12.2 Working with short circuits (and tracing circuits)
When the FF300T detects a short circuit (or closed circuit), it injects pulses of
electrical current in the wires, which generate magnetic fields. Unlike radio signals,
magnetic fields are not easily absorbed by nearby conductors and therefore can be
picked up by the FF300R (tracer) probe in a wider range of situations (See Fig. 7).